A mobile station, which usually comprises a transceiver and an identification module, normally stores personal, user-related data records from a wide variety of data categories (for example telephone numbers, addresses, appointments, texts and voice recordings). In addition, services (for example Internet, e-mail) are provided. When the mobile station is in the off state, the data records and services are generally protected against unauthorized access and unauthorized use, and also unauthorized call setup is stopped, since the prior art usually requires a personal identification number (PIN) to be input into the mobile station by the user using the keypad in order to turn on the mobile station and to activate its standby mode. It is thus usual practice on mobile telephones, for example, for startup of these appliances to be followed by a request for an ordinarily four-digit PIN, whose correct input is absolutely necessary in order to register in the network operator's network. This ensures that mobile telephones which are off hold no incentive for thieves because it is not possible to use them without prior PIN input.
Even if this protection function on mobile telephones which are not continuously carried by the users has authorization for these users, it is to some extent perceived as onerous to individualize authorized use by inputting the PIN in order to put the mobile telephone into the standby state first. The PIN therefore affords the protection that a mobile station is either protected only in the off state or is generally available in the standby state. This means that there is the risk of unauthorized use or theft particularly when the mobile station is in the standby state and is left unattended by the authorized user.
If the mobile station is in the standby mode, i.e. it is possible either for a call to the base station to be initiated by the mobile station or for the mobile station to receive a call initiated by the base station, there has previously been no possibility of person-related protection of the data or services provided via the mobile station.
In the case of one known apparatus (DE 299 15 915 U1), access to a service and/or a data record in the mobile station's standby mode is protected by virtue of the mobile station having a built-in transmitter with a mini-receiver. The built-in transmitter operates on a radio basis and in no way impairs the mobile telephone's operation while the mini-receiver is in the reception range. In this case, the mini-receiver is located on the mobile telephone owner's set of keys. If the owner now moves more than two to five meters away from his mobile telephone, the mini-receiver immediately gives an audible and visual alarm, and at the same instant the mobile telephone's keypad is locked. When the mobile telephone owner comes back into the transmission range, the keypad is immediately unlocked and is available again. To deactive the security system, the mini-receiver is turned off, and although this locks the keypad it is possible to use a code number (which is available to every mobile telephone) to unlock the keypad again.
The keypad lock usually implemented, which is known from the prior art in quite a few embodiments, is not a person-related means of protection, but rather just an, at best, appliance-specific mechanism for protecting against unintentional keypad operation.
Often, the mobile station is operated in the standby state for a relatively long time and is kept at locations which are accessible to a plurality of persons. Particularly in such situations or when the mobile station has been stolen in the standby state, it is useful to protect against misuse and unauthorized access to services and/or data records.